There has been significant recent interest in solution-processable organic-inorganic perovskite absorbers in solar cells following demonstrations of power conversion efficiencies exceeding the highest reported values for organic and dye-sensitized solar cells. However, to date, the highest efficiencies have been achieved using an electron collection (hole-blocking) layer which still requires sintering at 500 °C for best performance, which is unfavourable for low-cost production, applications on plastic substrates, and fabrication of multi-junction device architectures for even higher efficiencies. Here we report a low-cost, solution-based deposition procedure utilising nanocomposites of graphene and TiO2 nanoparticles as the electron collection layers in meso-superstructured perovskite solar cells. The graphene nanoflakes act as a continuous 2D conductive framework to provide superior charge-collection in the nanocomposites, enabling the entire device to be fabricated at temperatures no higher than 150 °C. These solar cells show remarkable photovoltaic performances with a power conversion efficiency (PCE) up to 15.6 % under simulated AM 1.5 solar illumination which is comparable to control devices using a standard TiO2 electron collection layer sintered at 500 °C. This work demonstrates that graphene/metal oxide nanocomposites have the potential to contribute significantly towards the development of low-cost solar cells.

In 2016 we have almost completed the collection that started with Nanostructured Energy Devices vol. 1. The next two volumes will be published in the CRC Press (Taylor&Francis) along 2017. The full collection will have the following Titles: Juan Bisquert. Nanostructured Energy Devices − Equilibrium Concepts and Kinetics (2014) Juan Bisquert. Nanostructur […]